Decrease of mitochondrial sensitivity to Ca2+-induced pore opening during long-term incubation
Akopova, O.V.; Sagach, V.F.
Ukrains'kyi Biokhimichnyi Zhurnal 76(5): 61-65
2004
ISSN/ISBN: 0372-3909 PMID: 16100898 Document Number: 567772
It is shown that mitochondria of rat myocardium exhibit high sensitivity to Ca2+-induced permeability transition pore (PTP) during an hour after their isolation. The threshold Ca2+ concentrations necessary to induce PTP are as low as 25-50 nmol/mg of protein. Apparent K(Ca) constant of Ca2+-dependent PTP activation is 40 microM. Incubation of mitochondria during 2, 3 and 4 hours after their isolation leads to gradual increase in K(Ca) values up to 0.4 microM, which is accompanied by simultaneous decrease in sensitivity of mitochondria to pore opening. A correlation is supposed between changes of kinetic parameters of Ca2+-uniporter and changes in sensitivity of mitochondria to Ca2+-induced permeability transition.